Health monitoring apps and wearables are a popular trend these days, and will only get hotter with Apple's HealthKit and Google Fit. However, a team at the MIT Wireless Center could take this trend much further by using a technology almost guaranteed to be found in any wired home.

The Computer Science and Artificial Intelligence Laboratory (CSAIL) in MIT Wireless Center has already developed a wireless technology that can track people through a wall by low-power signal that reflects back and reveals movement, much like radar.

In a newly published report, the team has expanded on that technology, which it called WiZ, to detect subtle movements such as the rise and fall of a person’s chest, which can determine a person's heart rate with 99% accuracy. The technology can also detect up to four distinct people in a room through the wall.

While the obvious use for such a technology would be law enforcement or military, the CSAIL team also sees use in more benign scenarios, such as a baby monitor, monitoring elderly or people on life support, and to serve as intrusion detection.

"It has traditionally been very difficult to capture such minute motions that occur at the rate of mere millimeters per second," writes Dina Katabi professor of electrical engineering and computer science at MIT in the research paper. She also directs the Wireless Center. "Being able to do so with a low-cost, accessible technology opens up the possibilities for people to be able to track their vital signs on their own."

Wi-Fi can penetrate walls, but not very well as anyone who has had to set up a signal repeater knows. Things can block the signal, like stucco walls and paints. Even when it does penetrate, the signal can be marred by other objects, so the team had to create technology to cancel out irrelevant reflections.

Eventually, the team hopes to improve the technology to the point it can generate silhouettes of the people and detect gestures and emotions.